In the case of a wide band wireless communication system, effective transmission/reception schemes and utilization schemes have been suggested in order to maximize the efficiency of limited radio resources. One of systems that are taken into account in the next-generation wireless communication system is a carrier aggregation system. A carrier aggregation system means a system for configuring a wide band by aggregating one or more carriers, each having a smaller bandwidth than a wide band that is a target, in order for a wireless communication system to support a wide band.
A wireless communication system, such as a conventional 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), uses carriers of various bandwidths, but it is one carrier, that is, single carrier system. In contrast, the next-generation wireless communication system, such as LTE-Advanced (A), can be a carrier aggregation system using an aggregation of multiple carriers, that is, a carrier aggregation.
In a single carrier system, for example, LTE, in uplink in which a mobile station transmits a signal to a base station, a single carrier property is used in order to efficiently utilize the power amplifier of the mobile station. The mobile station uses a control region in which control information is transmitted and a data region in which data is transmitted independently and does not send signals in the control region and the data region at the same time in order to maintain a single carrier property.
In contrast, in a carrier aggregation system, for example, LTE-A, simultaneous transmission in the control region and the data region may be permitted or not permitted depending on a configuration. In a carrier aggregation system, if simultaneous transmission in the control region and the data region is not permitted, a mobile station may need to send control information and data at the same time at a specific point of time. In this case, the mobile station may send the control information and the data in the data region at the same time. This is said that the control information is piggybacked (or multiplexed) and transmitted.
In a carrier aggregation system, if transmission in a data region using a plurality of carriers is scheduled at a point of time at which a mobile station must send control information, there is a problem in that whether the control information has to be piggybacked and transmitted on the data region of what carrier is not clear.